/* Copyright  (c) 2002 Graz University of Technology. All rights reserved.
 *
 * Redistribution and use in  source and binary forms, with or without 
 * modification, are permitted  provided that the following conditions are met:
 *
 * 1. Redistributions of  source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in  binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment:
 * 
 *    "This product includes software developed by IAIK of Graz University of
 *     Technology."
 * 
 *    Alternately, this acknowledgment may appear in the software itself, if 
 *    and wherever such third-party acknowledgments normally appear.
 *  
 * 4. The names "Graz University of Technology" and "IAIK of Graz University of
 *    Technology" must not be used to endorse or promote products derived from 
 *    this software without prior written permission.
 *  
 * 5. Products derived from this software may not be called 
 *    "IAIK PKCS Wrapper", nor may "IAIK" appear in their name, without prior 
 *    written permission of Graz University of Technology.
 *  
 *  THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE LICENSOR BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 *  OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 *  OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 *  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY  OF SUCH DAMAGE.
 */

package iaik.pkcs.pkcs11.wrapper;

import iaik.pkcs.pkcs11.TokenException;

import java.util.Properties;



/**
 * This is the superclass of all checked exceptions used by this package. An
 * exception of this class indicates that a function call to the underlying
 * PKCS#11 module returned a value not equal to CKR_OK. The application can get
 * the returned value by calling getErrorCode(). A return value not equal to
 * CKR_OK is the only reason for such an exception to be thrown.
 * PKCS#11 defines the meaning of an error-code, which may depend on the
 * context in which the error occurs.
 *
 * @author <a href="mailto:Karl.Scheibelhofer@iaik.at"> Karl Scheibelhofer </a>
 * @version 1.0
 * @invariants
 */
public class PKCS11Exception extends TokenException {

  /**
   * The name of the properties file that holds the names of the PKCS#11 error-
   * codes.
   */
  protected static final String ERROR_CODE_PROPERTIES = "iaik/pkcs/pkcs11/wrapper/ExceptionMessages.properties";

  /**
   * The properties object that holds the mapping from error-code to the name
   * of the PKCS#11 error.
   */
  protected static Properties errorCodeNames_;

  /**
   * True, if the mapping of error codes to PKCS#11 error names is available.
   */
  protected static boolean errorCodeNamesAvailable_;

  /**
   * The code of the error which was the reason for this exception.
   */
  protected long errorCode_;

  /**
   * Constructor taking the error code as defined for the CKR_* constants
   * in PKCS#11.
   * 
   * @param errorCode The PKCS#11 error code (return value).
   */
  public PKCS11Exception(long errorCode) {
    errorCode_ = errorCode;
  }

  /**
   * This method gets the corresponding text error message from
   * a property file. If this file is not available, it returns the error
   * code as a hex-string.
   *
   * @return The message or the error code; e.g. "CKR_DEVICE_ERROR" or
   *         "0x00000030".
   * @preconditions
   * @postconditions (result <> null)
   */
  public String getMessage() {
    // if the names of the defined error codes are not yet loaded, load them
    if(errorCodeNames_ == null) {
      synchronized (this.getClass()) {
        if (errorCodeNames_ == null) { // ensure that another thread has not loaded the codes meanwhile
          Properties errorCodeNames = new Properties();
          try {
            errorCodeNames.load(getClass().getClassLoader().getResourceAsStream(ERROR_CODE_PROPERTIES));
            errorCodeNames_ = errorCodeNames;
            errorCodeNamesAvailable_ = true;
          } catch(Exception exception) {
            System.err.println("Could not read properties for error code names: " + exception.getMessage());
          }
        }
      }
    }

    // if we can get the name of the error code, take the name, otherwise return the code
    String errorCodeHexString = "0x" + Functions.toFullHexString((int)errorCode_);
    String errorCodeName = errorCodeNamesAvailable_ ? errorCodeNames_.getProperty(errorCodeHexString) : null;
    String message = (errorCodeName != null) ? errorCodeName : errorCodeHexString;

    return message;
  }

  /**
   * Returns the PKCS#11 error code.
   *
   * @return The error code; e.g. 0x00000030.
   * @preconditions
   * @postconditions
   */
  public long getErrorCode() {
    return errorCode_ ;
  }

}